2

Larva currens?:
Larva currens is an itchy skin condition caused by a parasite called strongyloides stercoralis. It is notable for the itchy rash that moves fairly quickly (sometimes inches per hour) under the skin. Although mostly found in tropical and sub-tropical countries, it can also occur in the southeastern us. You need to be seen by a dermatologist or infectious disease doctor asap.
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3

Spider bite lesions:
Have extremely variable presentations. There isn't a way to tell you if the swelling is related to a spider bite. Dermatological evaluation may help to determine the cause for your symptoms.
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5

Hard to know:
Bruising is common with mosquito stings.Right after being bitten by a mosquito you may develop a soft white bump than later transitions into a hard, brown (reddish-brown) or a blister or bruising. There may be itching & swelling around the lesion.
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8

Hard to say:
Bed bugs usually feed off and on for hours and cause dozens of evident bites on the victim. Significant spider bites leave a dark hole. Single bites could be many things and is often not amenable to anyone determining their origin.
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9

Hard to say:
About the only way you know for sure what bug has bit you is to catch it in the act. The body responds to bites in a similar fashion that is specific to the person & their sensitivity to the bug. Some react minimally, some with advanced swelling, some go to the ER with a major event. What you describe is an arthus reaction which is common to many types of bites.
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10

Not a bug bite:
I would really doubt this is an insect bite. Most insect bites end up being an infection that is caused by MRSA or methcillin resistant staph aureus. If this bump is sore, i would get it checked out to make sure it doesn't need further treatment.
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12

Anything possible:
Without seeing either the bite or the biter would only be speculating, but mosquito bites seldom produce scabs unless you have scratched them open. Do you have bedbugs? A pet with fleas?
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14

Yes and no:
Most people get a local allergic reaction to mosquitoes. This will lead to a large area of redness. Some people are more allergic than others, so those people get even worse rashes and reactions. There are some lucky people who are not allergic at all. So while it is an allergic reaction, there is usually nothing dangerous about it. Oral antihistamines might help.
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16

Need exam:
There are a few kinds of bug bites that take longer to heal than others. Some spider bites and tick bites could fit what you describe, but melanoma is also on the list. If it hasn't gone away in 14 days you should see your dermatologist or primary care physician.
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20

Could be:
Look for an entry point in your skin for the possibility of this being an insect bite. If no punctae site-may be a mild traumatic injury that you don't recall. Either way-things should improve over 1-2 weeks. If any pain/tenderness/redness continues to evolve-see doctor.
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